October 2012. Post-mortem results of thousands of UK waterbirds reveal that poisoning from spent lead shot is still a major cause of death more than ten years after legislation was introduced to reduce the threat.

The analysis is published alongside the results of blood samples taken from live waterbirds caught in Britain within the last two years, which show that more than one in three of the birds sampled were affected by lead poisoning.

Lead is toxic and most uses of lead have systematically been phased out over the last three decades. However lead remains the most common material for shot in the UK. Waterbirds eat spent lead shot when feeding and taking in grit to help grind food in their gizzards. As the lead is absorbed into their bodies, it affects virtually every system. For example, it paralyses stomach muscles, causing food to become packed into the intestine, and birds can die of starvation.

Shooting

Some restrictions on shooting with lead shot have gradually been introduced across the UK but they do not cover most shooting over agricultural land, where many swan and goose species graze. Studies have also shown that in England there is little compliance with the current laws with many shooters freely admitting they use lead illegally.

Martin Spray is Chief Executive of The Wildfowl & Wetlands Trust (WWT), which funded and carried out the research. Speaking from the former home of Sir Peter Scott, shooter turned conservationist and founder of WWT, he said: “WWT has studied the effects of lead shot on ducks, geese and swans for decades, stretching back to Sir Peter Scott’s days. It is as clear today as it was then that in the UK lead poisoning from shooting kills a large number of our wild birds each year and makes many more very sick. Despite the law, brought in over a decade ago to protect wetland birds, nothing has changed. Clearly an effective solution is long overdue.”

10% water birds killed by lead poisoning

Fourteen species of ducks, geese and swans were found to have died from lead poisoning. Lead poisoning accounts for at least one in ten dead waterbirds recovered across Britain between 1971 and 2010. Dead birds were found with up to 438 pieces of lead shot in their gizzards.

The researchers specifically looked for the impact of legislation designed to protect the birds. Most sizes of lead angling weight have been banned from sale since 1988. It has been illegal to shoot certain species with lead and shoot with lead over certain wetlands in England since 1999, with similar legislation being adopted in Wales, Scotland and Northern Ireland. Across all species they could find no significant change in the proportion of birds dying from lead poisoning.

Mute swans benefitting from lead ban

However, one species, the mute swan was shown to benefit significantly from the ban on lead angling weights. The study showed that the proportion dying from lead poisoning dropped from a quarter to fewer than one in twenty.

Martin Spray explains: “Those of us over a certain age clearly remember lead angling weights being phased out around the same time as leaded petrol. It is wonderful that the link with the recovery of mute swan numbers has been supported by our research. Unfortunately it hasn’t directly benefitted other species but if we can learn anything from the way the law was designed and implemented, perhaps they will benefit indirectly.”

Mute swans are particularly prone to swallowing lost fishing weights as they feed along the banks of rivers and lakes. Most sizes of lead weight were completely banned from sale in 1986.

Grazing birds suffer

Many waterbirds, such as whooper swans, graze on agricultural land where it is still legal to shoot most species with lead shot. A single shotgun cartridge contains up to 300 pieces of lead shot, almost all of which fall to the ground after being fired.

Chris Perrins, LVO, FRS, Emeritus Fellow of the Edward Grey Institute at Oxford University, has been the Queen’s Warden of the Swans since 1993. His research into lead poisoning of mute swans built the case for the restrictions on the sale of lead angling weights. He said: “I find it extraordinary that we are still using lead [for shooting]. The Royal Commission on Environmental Pollution dealt with lead in 1983. One of its recommendations was [to phase out] all lead shooting shot and all lead fishing weights. Yet here we are nearly 30 years on and we are still using them.”

Phasing out the use of lead shot is recognised as the solution to protecting waterbirds from lead poisoning by the African-Eurasian Waterbird Agreement, an international treaty that the UK is signed up to. Lead shot is completely banned for shooting in Denmark, the Netherlands and Norway.

Martin Spray continues: “Considering that the law currently isn’t protecting waterbirds in Britain the way it is meant to, the most practical and effective solution would appear to be to extend the restrictions on the use of lead shot to cover all shooting.

“Non-toxic alternatives are available and have been used successfully for years in countries such as Denmark. Spokespeople for the shooting community have always said that, when the evidence is forth coming, they will support practical proposals to address the threat to wildlife. We very much look forward to working with them.”